It's my last question just nee because i'm dumb

c.171

Step-by-step explanation:

add the ones in the parentheses first and square it. we get 7^2=49. ow, multiply by 4 as multiplication comes next. we get 196. square 5. 5^2=25. 196-25=171.

∠acb = 8°

step-by-step explanation:

∠xba lies on the circle and is half the measure of the intercepted arc ax

hence

measure of arc ax = 2 × 42° = 84°

∠acb is outside the circle and is

∠acb = (arcab - arcax ), hence

∠acb = 0.5 (100 - 84) = 0.5 × 16° = 8°